Obtaining a quick and accurate overview of climate model data is often complicated or time consuming due to the large amount and complex structure of the data. This is particularly true for international collections of multi-model ensemble data sets containing contributions from many different modelling centers. Incomplete data sets, the use of non-standard units or missing files can complicate data analysis significantly. Additionally, some climate models simulate the regional climate poorly or have strong systematic biases, which is why future simulations of these models should be used cautiously. Especially in complex calculations, such model properties can be overseen, despite the influence on the results and on their interpretation.